The experiment on the opening width and height of compound artificial sand dunes in fishway

• Main Author: 蘇國振
• Other Authors: 段錦浩
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/67967256496685261919

碩士 === 國立中興大學 === 水土保持學系 === 90 === The installation of open sand dunes makes it feasible to increase the flow depth and reduce the flow velocity in fishway. Meanwhile, it should be noted that the state of water flow in fishway is significantly dependent on the width and the height of sand dune opening. In this study, the dimension effect of sand dune opening on the flow state in fishway was extensively investigated. Based on the experimental ideal spacing of sand dune, 0.74m, which was adopted in the paper entitled “The Experiment on the Density of Artificial Sand Dune with Opening in Fishway, C.T. Kao, 2001”, a series of experiments were conducted for 9 types of sand dunes, 3 discharge capacities and 3 inclined slopes to study the performances of flow depth, flow velocity, specific energy and sedimentation (or adding sands). According to the testing results, the installation of various types of sand dune may result in an increment over 200% for the average flow depth and a decrement over 20% for the flow velocity. The influence of the width of sand dune opening on raising the flow level and reducing the flow velocity in fishway is more significant than that of the height of opening. In further, it was found that the sediment deposit of sand material occurs in all cases of sand dune with various inclined slopes. However, most of the sand material settles at the both sides of opening. As a result, the fishway can still provide a free flow path without any clogging. In experiments, the behavior of sedimentation for various types of sand dune was also investigated. It is found that the sedimentation can be largely mitigated for the sand dune with the dimension of 15cm in width and 10cm in height. It is also expected that these findings can be employed as a reference in the similar design of engineering practice.